数据库连接的5种方式_数据库连接方式

数据库连接的5种方式

        String url = "jdbc:mysql://localhost:3306/njustzjc1";
        Properties properties = new Properties();
        properties.setProperty("user","root");
        properties.setProperty("password","zjc");
        Driver driver = new Driver();
        Connection connect = driver.connect(url, properties);
        String sql = "insert into jdbc values(1,'zjc')";
        Statement statement = connect.createStatement();
        int i = statement.executeUpdate(sql);
        statement.close();
        connect.close();
1
2
3
4
5
6
7
8
9
10
11

  String path = "com.mysql.jdbc.Driver";
        Class<?> aClass = Class.forName(path);
        Object oo = aClass.newInstance();
        Driver o = (Driver) oo;
        String url = "jdbc:mysql://localhost:3306/njustzjc1";
        Properties properties = new Properties();
        properties.setProperty("user","root");
        properties.setProperty("password","zjc");
        Connection connect = o.connect(url, properties);
        String sql = "delete from  jdbc  where id = 1";
        Statement statement = connect.createStatement();
        int i = statement.executeUpdate(sql);
        System.out.println(i > 0 ? "成功":"失败");
        statement.close();
        connect.close();
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

 //方式3 使用DriverManager 替代 driver 进行统一管理
    @Test
    public void connect03() throws IllegalAccessException, InstantiationException, ClassNotFoundException, SQLException {

        //使用反射加载Driver
        Class<?> aClass = Class.forName("com.mysql.jdbc.Driver");
        Driver driver = (Driver) aClass.newInstance();

        //创建url 和 user 和 password
        String url = "jdbc:mysql://localhost:3306/hsp_db02";
        String user = "root";
        String password = "hsp";

        DriverManager.registerDriver(driver);//注册Driver驱动

        Connection connection = DriverManager.getConnection(url, user, password);
        System.out.println("第三种方式=" + connection);
    }
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

更简单的方式：

底层有静态代码块帮助我们完成了registerdriver的事情

 //创建url 和 user 和 password
        String url = "jdbc:mysql://localhost:3306/hsp_db02";
        String user = "root";
        String password = "hsp";
        Connection connection = DriverManager.getConnection(url, user, password);

        System.out.println("第4种方式~ " + connection);

    }
1
2
3
4
5
6
7
8
9

//方式5 , 在方式4的基础上改进，增加配置文件，让连接mysql更加灵活
    @Test
    public void connect05() throws IOException, ClassNotFoundException, SQLException {

        //通过Properties对象获取配置文件的信息
        Properties properties = new Properties();
        properties.load(new FileInputStream("src\\mysql.properties"));
        //获取相关的值
        String user = properties.getProperty("user");
        String password = properties.getProperty("password");
        String driver = properties.getProperty("driver");
        String url = properties.getProperty("url");

        Class.forName(driver);//建议写上

        Connection connection = DriverManager.getConnection(url, user, password);

        System.out.println("方式5 " + connection);

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

1. class.forname（）实际上可以不写
   
2. url的解释：